Bio 101 Exam 2

2 types of cell division in Eukaryotes

Meiosis and mitosis

Meiosis

Leads to production of GAMETES

Mitosis

Leads to production of all other cell types, Division of nucleus

Somatic cells

All cell types besides gametes

Cell division in Prokaryotes

Binary Fission

Cytokinesis

Division of cytosol/other organelles

Functions of Mitosis

1. Growth 2. repair/replacement 3. Asexual reproduction

Diploids

Cells/ organs that have paired chromosomes

Haploid

Cells/ organisms with unpaired chromosomes

Sister Chromatids

Replicated chromosomes

Centromere

Region where sister chromatids attach

Cohesins

Act like glue connecting sister chromatids

Kinetochore

Protein structure where microtubules attach during mitosis

G1 + S + G2 stages

Interphase

G0

resting stage, gets signal to divide

G1

Cell growth, transcription/translation, prepare for DNA replication

S

DNA replication

G2

More growth, transcription/translation, prepare to divide. centrosomes appear

M

Mitosis, divided into 4 stages: Prophase, Metaphase, Anaphase, Telophase/cytokinesis

Prophase

Chromosomes condense, Nuclear envelope disappears, Centrisomes migrate to opposite sides of the cell, Miotic spindle forms, Kinetochore MT’s attach to kinetochores, non-kinetochore MT’s do not attach to kinetochores

Metaphase

Chromosomes line up on metaphase plate, 4 chromosomes, 8 sister chromatids

Anaphase

Separation of DNA, Cohesion proteins degrade, kinetoshore MT’s shorten, Sister chromatids separate from each other and move to opposite sides of the cell, 8 chromosomes and 0 sister chromatids

Telophase/ cytokinesis

Chromosomes decondense, Nuclear envelope reassembles, miotic spindle and centrisomes disappear, Microfilaments shorten and tighten to pinch cell in 2

Binary fission

DNA replicates, replication separates from original, cell splits in 2

Cell cycle control

G1 → S → G2 → M

Checkpoint

Critical point in cell cycle that is regulated, regulatory molecules at each point “decide” if division should proceed

G1 Checkpoint

Is growth factor present? Is cell big enough? Is DNA undamaged

G2 Checkpoint

Is DNA replication complete?

metaphase checkpoint

Are chromosomes attached to kinetochore MT’s?

If problem with cell 2 options

Problem gets fixed or apoptosis

Apoptosis

Cell suicide pathway

Growth factors

Stimulate cells to divide, make sure cells start and stop reproducing at the right time, has a specific receptor

Growth factor pathway/ signal transduction

External signal → internal response

Reception

Signal binds to receptor → receptor is activated

Transduction

Relay molecules in pathway get activated

Response

Activation of cellular response → cells start or stop dividing

Anchorage dependece

Cells must be attached to something to divide (other cells, extracellular matrix, or tissue culture plastic)

Contact Inhibition

Crowded cells stop dividing

Benign Tumor

Not cancerous, sticks to one area

Malignant Tumor

Cancerous, invade neighboring tissue

Metasis

Cells ignore anchorage dependence and unattach from others to go through bloodstream to travel to other parts of the body

Proto-oncogenes

genes that encode signals, receptors, signaling molecules, control proteins

Oncogenes

Mutated genes → cancer-causing genes

Gene amplification

Turns proto-oncogenes into oncogenes, cell has too many receptors and divides too quickly

Translocation

a chunk of chromosome attaches to a different chromosome

Tumor- suppressor proteins

Inhibit cell division, shut down cell if conditions not favorable, normal cell proteins

BRCA1 and BRCA2

Helps repair damaged DNA at G2 checkpoint, tumor suppressor

P53

Works at G1 checkpoint, tumor suppressor

3 stages of sexual reproduction

Meiosis (egg and sperm formation), fertilization, mitosis (growth and developement)

Autosomes

all chromosomes that aren’t sex chromosomes

Abnormal Methylation

hyper-methylated → gene shut off

too many methyl groups are on the gene, no tumor made, cell cycle control is compromised

Anti-sense molecule

single-stranded nucleic acid complementary to RNA we want to inhibit

Genetic Variation due to

Mutation, Random alignment of chromosomes on metaphase 1 plate, crossing over, fertilization

Haploid

n=23

Diploid

2n=46

Euploid

An exact or multiple of a haploid number: n, 2n, 3n

Aneuploid

Any chromosome number that is not euploid: 2n=46+1

Nondisjunction

Homologous chromosomes or sister chromatids don’t separate from each other

Blending Inheritance Theory

The genetics of the parents mix

Particulate Inheritance Theory

Parents pass on certain genes that keep their distinction but can also mix

Gregor Mendel (1822-1884)

Monk and gardener who studied genetics

Dominant

One trait seen

Recessive

Trait hidden

Alleles

Hereditary factors resulting in contrasting traits

Genotype

Combination of alleles in an individual (gene)

Phenotype

Expression of a trait (Physical characteristics)

Segregation

Genes come in pairs that separate from one another in the formation of gametes

Heterozygous

2 different alleles

Homozygous

Same alleles (can be homozygous dominant or recessive)

Genotypic Ratio

1PP: 2Pp: 1pp

Gametes are haploid so they:

Have half the number of chromosomes

Trisomic

Extra copy of a chromosome

Monosomic

Missing a chromosome

Alteration in chromosome structure

Deletion, duplication, inversion, reciprocal translocation

Test cross

Cross unknown to homozygous recessive

Cellular Respiration

Breakdown of organic fuels to make ATP

Aerobic Cellular Respiration

Cellular respiration with oxygen present

ATP

Adenosine Triphosphate

ADP

Adenosine Diphosphate

Substrate-level phosphorylation

Accounts for all ATP made in glycolysis and citric acid cycle

Mitochondria has

Outer membrane, inner membrane, intermembrane space, matrix

Inner mitochondrial membrane

Folds: cristae increase surface area

NAD+ and FAD

Electron shuttles, take e-’s from food and transfer to shuttles which takes e-’s to electron transport chain

Cellular Respiration stages

Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation

Glycolysis

Glucose breaks down and makes 2 pyruvates, happens in cytosol, makes 2 ATP and 2 NADH

Pyruvate Oxidation

Conversion of pyruvate to Acetyl CoA, Co2 released, happens in matrix

Citric Acid Cycle (krebs cycle)

Conversion of 2 Acetyl CoA to 2 Co2, 3 NADH, 1 ATP and 1 FADH (happens twice) Occurs in the matrix

Oxidative Phosphorylation

Electrons are passed down electron transport train, H+ gradient is formed, and H+ flows through ATP synthase, 26-28 ATP made

Electron Transport Chain

Collection of molecules embedded in inner mitochondrial membrane

What is the order that animals exchange materials with the environment?

Digestion, respiration, circulation, excretion

How does exchange of materials occur?

Substances are dissolved in an aqueous solution and move across the plasma membrane of each cell

Simple Animals

Can have direct exchange with environment

Simple Animal Characteristics

Thin flat shape, very few cell layers, live in moist environments

Complex Animals

Specialized exchange surfaces

Complex Animal Characteristics

Made of living cells, thin, large surface area, moist, connected to circulatory system

Fermentation

Respiration when no oxygen is present

Salivary Amylase

Breaks down starch/ polysaccharides (In Mouth)

Peristalsis

Pushes down food bundle (throughout whole alimentary canal)

Gastric Juice

Digests meat (protein) made of hydrochloric acid and pepsin (in stomach)

Parietal cell

Secretes H+ and Cl which becomes hydrochloric acid